On 8/26/21 12:17 AM, Liu Zixian wrote:
After fork, the child process will get incorrect (2x) hugetlb_usage. If a process uses 5 2MB hugetlb pages in an anonymous mapping, HugetlbPages: 10240 kB and then forks, the child will show, HugetlbPages: 20480 kB The reason for double the amount is because hugetlb_usage will be copied from the parent and then increased when we copy page tables from parent to child. Child will have 2x actual usage.
Fix this by adding hugetlb_count_init in mm_init.
Fixes: 5d317b2b6536 ("mm: hugetlb: proc: add HugetlbPages field to /proc/PID/status") Signed-off-by: Liu Zixian liuzixian4@huawei.com
v2:
- Create two hugetlb_count_init in hugetlb.h instead of using #ifdef
in fork.c 2. Add an example to clearify this issue.
include/linux/hugetlb.h | 9 +++++++++ kernel/fork.c | 1 + 2 files changed, 10 insertions(+)
Thanks,
Reviewed-by: Mike Kravetz mike.kravetz@oracle.com
Andrew, can you add a CC stable?